Mercury dispensing station



Dec. 21, 1965 D Y ETAL 3,224,651

MERCURY DISPENSING STATION 23 FIG.I

Filed Dec. 24, 1965 DAVID R. DAYTON DAVID N BROOKS INVENTORS T RNEYFIG.2

United States Patent 3,224,651 MERCURY DISPENSING STATTON David R.Dayton, Beverly, and David N. Brooks, West Peabody, Mass, assignors toSylvania Electric Products Inc, a corporation of Delaware Filed Dec.24-, 1963, Ser. No. 333,118 12 Claims. (Cl. 222-361) This inventionrelates to mercury dispensing stations which can be used in themanufacture of high pressure discharge devices containing mercury andhalogens and particularly to stations which can dispense very small,uniform and easily varied quantities of mercury.

Mercury dispensing stations are well known to the art, however, beforethe introduction of high pressure discharge devices containingrnercury-halogen fills, precision in the quantities of mercuryintroduced into the arc tube of the device was not always important. Inthe older high pressure electric discharge devices containing mercuryalone, fairly wide tolerances were allowed and hence, the equipment didnot have to be designed to dispense critical dosages. And furthermore,because the light emission and color rendition of the mercury-halogencontaining high pressure electric discharge devices can be modified bychanging the quantity of mercury relative to the halogen, it has becomedesirable to use dispensing stations in which these critical dosages maybe easily varied. Additionally, the stations of the art dispensed onlyrelatively large quantities of mercury whereas our device can dispensesmall and critical dosages.

The primary object of our invention is dispensing uniform, criticalquantities of mercury into high pressure electric discharge devices.

Another object of our invention is the provision of equipment in whichsmall quantities of mercury are dispensed into discharge devices andwhich can be easily varied when desired.

A feature of our invention is transferring mercury from a reservoir intothe arc tube of a discharge device with the inner ends of a pair ofopposing slide rods, the distance between which is adjustable.

An advantage of our invention is that a small volume of mercury can betransferred quantitatively from a reservoir to an arc tube.

The many other objects, features and advantages of our invention willbecome manifest to those conversant with the art upon reading thefollowing specification when taken in conjunction with the accompanyingdrawings wherein preferred embodiments of our mercury dispensing stationare shown and described by way of illustrative examples and wherein theprinciples of our invention are explained.

Of these figures:

FIGURE 1 is a cross-sectional view of the mercury dispenser according toour invention.

FIGURE 2 is a perspective view particularly illustrating the dispositionof the slide rods which control the quantity of mercury added to the arctube.

Referring now to FIGURE 1 of the drawings, the mercury reservoir 1 isdisposed within pressure tight casing 2 which is secured to the baseplate 3 by means of clamping ring 4 butting against shoulder 5. AnO-ring gasket 32 is placed in a groove formed in shoulder 5 to maintainthe desired pressure and keep the dispenser free of contamination byatmospheric gases.

The reservoir 1 preferably is funnel shaped at the bottom extending intoa closed-end, column portion 6 of reduced diameter. A longitudinallyextending bore having sections 7 and 8 is disposed through the lowerportion of the reservoir into the column 6. A pair of opposed slide rods9 and 10 are fitted into the bore and adapted to slide therein.Preferably, the spacing of the slide rods and the bore is quite close sothat mercury leakage therebetween can be eliminated. The internal endsof the rods 9 and 10 are spaced from each other by a distance whichdetermines the quantity of mercury which will be transferred to the arctube. Preferably the distal end of slide rod 9 is welded to a screw head12. fitted into a U-shaped yoke 11 so that the distance between theinternal ends of the rods can be adjusted in fine increments whendesired. A rough adjustment in the mercury dosage can be obtained bymoving rod 10 with a screw tightened clamp formed in the end of the yoke11. When the screw 26 is loosened, the rod 10 can be easily moved withinthe clamp.

In order to transfer very small quantities of mercury from a reservoirto an arc tube, we have discovered that the diameter of the rods shouldbe less than the spacing between the opposing inner ends. In this waywhen the mercury from the reservoir 1 is moved to a position over thetransfer conduit 14, the mercury must fall because of its own weight.Immediately upon movement of the mercury load to a position over thetransfer conduit 14, a mercury sphere forms. Since the diameter of thesphere is less than the spacing between the rods 9 and 10, the mercurywill touch the equipment at one point only.

Disposed at the side of the column 6 is a reservoir transfer conduit 14which extends downwardly in a straight line to base plate transferconduit 30. An exhaust tube 15 of an arc tube 16 can be disposed at theend of the transfer conduits by conventional means.

Hence when yoke 11 is laterally drawn, the rods 9 and 10 will movewithin bores 7 and 8 respectively to a point where they eventually willbe disposed over transfer conduit 14 and the dosage of mercury will thenfall out and drop by gravity. The freely falling mercury will fall intothe arc tube 16 through exhaust tube 15.

If it is desired to impel the mercury into the arc tube with greatervelocities, a blast of gas may be downwardly directed into the transfercolumn.

Movement of the yoke 11 may be accomplished by many different means suchas a draw bar in the side of the casing 2, an electromagnetic force orsometimes attaching a solenoid' The preferred arrangement, however,which we have shown includes a crankshaft 17 at the end of which wemount an eccentrically disposed pin 13. Pin 13 is loosely fitted in agroove 33 cut into yoke 11 so that when the knob 18 is rotated, yoke 11will be drawn in the direction of the arrow. Preferably shaft 17 ismounted in guide block 19 through the top of the casing 2. In order toprevent the pin 13 from falling out of the yoke groove 33, we prefer tomount a stop pin 20 in the O-ring cap 22. Pin 20 can then fit into acooperating groove 23 and prevent the knob 13 from being rotated toofar. To automate the dispenser, a cam can be easily substituted for knob18.

Chamber 24 is used to convey flush gases to and from the arc tube 16through the upper section of the transfer conduit. The upper section ofthe transfer conduit is in a gas flow relationship with the chamber 24which in turn is attached to external gas lines (not shown).

The perspective view of our mercury dispenser is shown in FIGURE 2. Thereservoir and the closed-end rod conduit 6 is shown in phantom lines.U-shaped yoke 11 carries the adjustable rod 9 which has a threaded screw34 mounted at the outer end. Preferably the adjustable rod 9 and thescrew are mounted within a screw biased slot within the yoke 11. Sliderod 10 is similarly mounted within a biased slot formed on the otherside of yoke 11 and tightened by screw 26. If a gross adjustment has tobe made in the mercury dosage, screw 26 can be loosened and slide rodmoved manually. Following the rough adjustment, a more precisemodification of the dosage can be made by turning screw 12 within itsslot.

Movement of crank shaft 17 by turning knob 18 will move the yoke 11 andin turn carry the opposed ends of a slide rod 9 and 10 from theiroriginal position in the closed end of column 6 to a new position overthe transfer conduit 14.

In operation, we prefer to fill the reservoir 1 with a large quantity ofmercury. An arc tube 16 with an exhaust tube is fitted into the end ofthe transfer conduit 14. Knob 18 is then turned and the yoke 11 is drawnin the direction of the arrow so that rods 9 and 10 will be moved to aposition over transfer conduit 14. When the opposed ends of slide rods 9and 10 move through the bore 8 they will carry with them the requisitedosage of mercury which in turn will fall into transfer conduit 14 bygravity and thence into arc tube 16. The yoke 11 is then returned to itsoriginal position with the rods 9 and 10 in the conduit 6.

It is apparent that modifications and changes may be made within thespirit and scope of the instant invention but it is our intention,however, only to be limited by the scope of the appended claims.

As our invention we claim:

1. A mercury dispenser comprising: a mercury reservoir; a closed endcolumn extending from said reservoir; a transfer conduit disposedalongside of said column; a bore extending through said reservoir andinto said column and thence into said transfer conduit; a pair ofopposed rods having their inner ends spaced from each other, slidablydisposed within said bore; means to move the spaced ends of said rodsfrom a position within said column to a new position over said transferconduit, said means being a U-shaped yoke disposed about said reservoirand the outer ends of said rods being held by said yoke.

2. The dispenser according to claim 1 wherein at least one of said rodsis adjustably positioned within said yoke.

3. A mercury dispenser comprising: a housing formed by a cover capmounted upon a base plate; a mercury reservoir disposed within saidhousing; a transfer conduit disposed alongside of said reservoir andthrough said base plate; a bore extending through said reservoir andinto said transfer conduit; a pair of opposed rods having their innerends spaced from each other slidably disposed within said bore; means tomove the spaced ends of said rods from a position within said reservoirto a new position over said transfer conduit.

4. A mercury dispenser comprising: a housing formed by a cover capmounted upon a base plate, a mercury reservoir disposed within saidhousing; a closed end column extending from said reservoir; a transferconduit disposed alongside of said reservoir and through said baseplate; a bore extending through said reservoir and into said column andthence into said transfer conduit; a pair of opposed slide rods havingtheir inner ends spaced from each other slidably disposed within saidbore; means to move the spaced ends of said rods from a position withinsaid reservoir to a new position over said transfer conduit.

5. The dispenser according to claim 4 wherein said means is a U-shapedyoke disposed about said reservoir and the outer ends of said rods areheld by said yoke.

6. The dispenser according to claim 5 wherein at least one of said rodsis adjustably positioned within said yoke.

7. A mercury dispenser comprising: a mercury reservoir; a transferconduit extending from said dispenser; a bore extending through saidreservoir and into said transfer conduit; a pair of opposed rods havingtheir inner ends spaced from each other slidably disposed within saidbore; a U-shaped yoke disposed about said reservoir and the outer endsof said rods being held by said yoke; a channel formed in one leg ofsaid yoke; a pin eccentrically mounted upon an end of a crankshaft,sildably engaged within the channel of said yoke; means to turn saidcrankshaft and thus rotate said pin thereby moving said yoke and hencethe inner ends of said rods from a position within said reservoir to anew position over said transfer conduit.

8. The dispenser according to claim 7 wherein at least one of said rodsis adjustably held by said yoke.

9. A mercury dispenser comprising: a mercury reservoir; a closed endcolumn extending from said reservoir; a transfer conduit extending fromsaid dispenser; a bore extending through said reservoir and into saidcolumn and thence into said transfer conduit; a pair of opposed rodshaving their inner ends spaced from each other slidably disposed withinsaid bore; a U-shaped yoke disposed about said reservoir and the outerends of said rods being held by said yoke; a channel formed in one legof said yoke; a pin eccentrically mounted upon an end of a crankshaft,slidably engaged within the channel of said yoke; means to turn saidcrankshaft and thus rotate said pin thereby moving said yoke and hencethe inner ends of said rods from a position within said reservoir to anew position over said transfer conduit.

10. The dispenser according to claim 9 wherein at least one of said rodsis adjustably held by said yoke.

11. A mercury dispenser comprising: a mercury reservoir; a closed endcolumn extending from said reservoir; a transfer conduit extending fromsaid dispenser; a bore extending from said reservoir and into saidcolumn and thence into said transfer conduit; a pair of opposed rodshaving their inner ends spaced from each other, slidably disposed withsaid bore, the spacing between the inner ends of said rods being greaterthan their diameters; means to move the spaced ends of said rods from aposition within said column to a new position over said transferconduit, said means being a U-shaped yoke disposed about said reservoirand the outer ends of said rods being held by said yoke.

12. The dispenser according to claim 11 wherein at least one of saidrods is adjustably positioned within said yoke.

References Cited by the Examiner UNITED STATES PATENTS 528,572 11/1894Thomas. 2,818,200 12/1957 Webb et al 222-194 LOUIS I. DEMBO, PrimaryExaminer.

3. A MERCURY DISPENSER COMPRISING: A HOUSING FORMED BY A COVER CAPMOUNTED UPON A BASE PLATE; A MERCURY RESERVOIR DISPOSED WITHIN SAIDHOUSING; A TRANSFER CONDUIT DISPOSED ALONGSIDE OF SAID RESERVOIR ANDTHROUGH SAID BASE PLATE; A BORE EXTENDING THROUGH SAID RESERVOIR ANDINTO SAID TRANSFER CONDUIT; A PAIR OF OPPOSED RODS HAVING THEIR INNERENDS SPACED FROM EACH OTHER SLIDABLY DISPOSED WITHIN SAID BORE; MEANS TOMOVE THE SPACED ENDS OF SAID RODS